Dissecting the role of mycobacterial cell envelope components and DNA in leprosy reactions

剖析分枝杆菌细胞包膜成分和 DNA 在麻风反应中的作用

• 批准号: MR/N017420/1
• 负责人: Gurdyal Besra
• 金额: $ 41.63万
• 依托单位: University of Birmingham
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FN017420%2F1
• 关键词: Dissecting; role; mycobacterial; cell; envelope

Leprosy, a chronic infectious disease caused by the bacterium Mycobacterium leprae, remains a public health threat in developing countries, including Brazil, where more than 30,000 new cases are reported annually. A major health concern for individuals suffering from leprosy is that the disease principally affects the skin and the peripheral nervous system, leading to sensorial impairment and permanent disabilities. Indeed, acute inflammatory reactive leprosy responses of the immune system to the leprosy bacillus are the leading cause of nerve damage. These episodes can occur in individual patients, long after they are considered cured and termination of anti-leprosy drug treatment. However, our understanding of the physiopathology of leprosy reactions remains limited, and further research is urgently needed if we are to understand the biology underlying this neglected disease. The overall aim of this study is to investigate the molecular basis of reactional episodes in leprosy patients. Our hypothesis is that M. leprae constituents can remain in host tissues for long periods of time, and are responsible for the immune activation that occurs in these patients during reaction. This study will bring together the varied and complementary expertise of investigators from The FIOCRUZ, Oswaldo Cruz Foundation (Brazil) and The University of Birmingham (UK) to investigate the involvement of mycobacterial lipids, cell wall fragments and DNA as triggers of the reactional episodes. The investigators based in Brazil are experts in leprosy, specifically the immune responses involved in the infection. Investigators in the UK are experts in the molecular genetics and biochemistry of the mycobacterial cell wall. The knowledge generated in this study can contribute to more effective treatments and management strategies for leprosy reactions, with a greater impact on the quality of life, not just in Brazil but globally, given that leprosy affects many developing countries.The main objectives of the study are:Objective I: The UK Team (University of Birmingham, UoB) will define diagnostic lipid and cell envelope component profiles of standard M. leprae, surrogate Mycobacterium haemophilum and leprosy biopsy material and assess the persistence of these compounds in biopsies from leprosy patients who have experienced a reaction at least two years after the conclusion of anti-leprosy treatment.Objective II: The Brazil Team (FIOCRUZ) will investigate the levels of M. leprae DNA and the involvement of the inflammasome pathways by analysing markers of inflammasome activation in leprosy biopsies of reactional lesions.Objective III: To use well-established extraction and purification protocols at UoB to provide specific cell envelope components for further studies in Objective IV by collaborators at FIOCRUZ (Brazil Team). This will include M. leprae components (e.g. PGL, PDIM, mycolic acids, muropeptides), including available previously purified material by the UK team and through BEI Resources (e.g. whole cells, LAM). Since, leprosy bacilli are uncultivable, M. haemophilum, a phylogenetically related surrogate of M. leprae, will also be used as a source of structurally-related M. leprae-type lipids and LAM for bulk purification. Truncated versions of M. haemophilum PGL and LAM will also be prepared. Objective IV: The Brazil Team (FIOCRUZ) will investigate which mycobacterial components identified in Objectives I and III are bioactive in inducing inflammatory mediators in whole blood samples of reactional patients. The most promising immune active components will be used to investigate their capacity to activate inflammasome pathways in in vitro differentiated macrophages and dendritic cells. Truncated versions of the active molecules will also be tested to map their functional moieties.

麻风病是一种由麻风分枝杆菌引起的慢性传染病，仍然是包括巴西在内的发展中国家的公共卫生威胁，巴西每年报告的新病例超过30 000例。麻风病患者的一个主要健康问题是，这种疾病主要影响皮肤和周围神经系统，导致感觉障碍和永久残疾。事实上，免疫系统对麻风杆菌的急性炎症反应性麻风反应是神经损伤的主要原因。这些事件可能发生在个别患者中，在他们被认为治愈和终止抗麻风药物治疗很久之后。然而，我们对麻风反应的生理病理学的理解仍然有限，如果我们要了解这种被忽视的疾病的生物学基础，迫切需要进一步的研究。本研究的总体目的是探讨麻风病人反应性发作的分子基础。我们的假设是M.麻风病的成分可以在宿主组织中保留很长一段时间，并且是这些患者在反应期间发生的免疫激活的原因。这项研究将汇集来自FIOCRUZ，Oswaldo Cruz基金会（巴西）和伯明翰大学（英国）的研究人员的各种和互补的专业知识，以调查分枝杆菌脂质，细胞壁碎片和DNA作为反应事件触发器的参与。巴西的研究人员是麻风病方面的专家，特别是与感染有关的免疫反应。英国的研究人员是分枝杆菌细胞壁的分子遗传学和生物化学方面的专家。在这项研究中产生的知识，可以有助于更有效的治疗和管理战略的麻风反应，对生活质量的影响更大，不仅在巴西，但在全球范围内，因为麻风病影响到许多发展中国家的研究的主要目标是：目的一：英国队（伯明翰大学，UoB）将定义诊断脂质和细胞包膜成分配置文件的标准M。麻风，替代嗜血分枝杆菌和麻风活检材料，并评估这些化合物的持久性，从麻风病人谁经历了反应后，至少两年的结论抗leprosy treatment.ObjectiveII：巴西队（FIOCRUZ）将调查M的水平。麻风DNA和参与的炎症体途径通过分析标记物的炎症体激活麻风活检的reactional lesions.ObjectiveIII：使用完善的提取和纯化协议在UoB提供特定的细胞包膜成分，为进一步研究的目标IV的合作者在FIOCRUZ（巴西队）。这将包括M。麻风病成分（例如PGL、PDIM、分枝菌酸、胞肽），包括英国团队和BEI Resources先前纯化的可用材料（例如全细胞、LAM）。由于麻风杆菌是不可培养的，M. haemophilum是M.麻风，也将被用作结构相关的M的来源。麻风型脂质和LAM用于批量纯化。M的截短版本。还将制备嗜血杆菌PGL和LAM。目标四：巴西团队（FIOCRUZ）将研究目标I和III中确定的分枝杆菌成分在诱导反应性患者全血样本中的炎症介质方面具有生物活性。最有前途的免疫活性成分将用于研究其在体外分化的巨噬细胞和树突状细胞中激活炎性体通路的能力。还将测试活性分子的截短形式以绘制其功能部分。